Tonic-Clonic Seizures

Dravet syndrome is a severe form of epilepsy caused by a genetic mutation. Symptoms, including seizures often accompanied by a high fever, generally begin in the first year of life.

Several different types of seizures can be seen in Dravet syndrome, the most dangerous of which are tonic-clonic seizures, sometimes called a generalized seizure or a grand-mal seizure.

What is a tonic-clonic seizure?

Tonic-clonic seizures are the ones with which people are most familiar. They are characterized by convulsions and loss of consciousness.

These seizures have two phases: tonic (stiffening) and clonic (rhythmical jerking).

When the seizure begins, all the muscles stiffen and the person loses consciousness. During the clonic phase, the arms and legs begin to jerk rapidly and rhythmically as the person convulses.

After a few minutes, the jerking slows and stops. The patient usually regains consciousness quickly, but may not be completely aware for a few minutes to an hour after the seizure.

A tonic-clonic seizure typically lasts for one to three minutes. Seizures lasting longer than five minutes, or multiple seizures in a row without the person regaining consciousness in between, are called status epilepticus and require immediate medical attention.

How are tonic-clonic seizures treated?

Maintaining a treatment regimen with anticonvulsants can reduce the occurrence and severity of tonic-clonic seizures, as well as other types. For Dravet patients, a ketogenic diet may also help reduce seizures.

Other information

Patients will usually not be aware of what happened during a tonic-clonic seizure. They may be confused, tired, or sleepy after the seizure.

Sometimes patients may bite their tongue or the inside of their cheek during a tonic-clonic seizure. Their muscles may be sore afterward.

It is important to have an emergency seizure management plan with patient information and treatment regimen so that emergency responders can treat the patient quickly.


Dravet Syndrome News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.